File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

CUR file extension

Windows Cursor

System Files

DEM file extension

Video Game Demo File

Game Files

EPUB file extension

Open eBook File

eBook Files

FON file extension

Generic Font File

Font Files

ICS file extension

iCalendar File

Misc Files

JAVA file extension

Java Source Code File

Developer Files

LOG file extension

Log File

Text Files

MID file extension

MIDI File

Audio Files

MSG file extension

Outlook Mail Message

Text Files

PAGES file extension

Pages Document

Text Files

PIF file extension

Program Information File

Executable Files

TAR file extension

Consolidated Unix File Archive

Data Files

TGA file extension

Targa Graphic

Raster Image Files

VCD file extension

Virtual CD

Disk Image Files

3G2 file extension

3GPP2 Multimedia File

Video Files